Fuel injection system



Oct. 31, 1961 J. F. ARMSTRONG ETAL 3,00

FUEL INJECTION SYSTEM 10 Sheets-Sheet 1 Filed April 6, 1959 awn ill-ll INVENTORS JAMES F. ARMSTRONG CHARLES K. M CONNELL ATTORNEY Oct. 31, 1961 J. F. ARMSTRONG EIAL 3,006,329

FUEL INJECTION SYSTEM Filed April 6, 1959 10 Sheets-Sheet 2 Q INVENTORS 7 JAMES F. ARMSTRONG CHARLES K. MCONNELL ATTORNEY 1961 .1. F. ARMSTRONG ETAL 3,006,329

FUEL INJECTION SYSTEM Filed April 6, 1959 10 Sheets-Sheet 3 F l G. 9. 2s?

F|G.|O. FIGII JAMES F. ARMSTRONG CHARLES K. MCONNELL ATTQRNEY Oct. 31, 1961 J. F. ARMSTRONG ETAL 3,006,329

FUEL INJECTION SYSTEM Filed April 6, 1959 10 Sheets-Sheet 4 k l t [63/ k I8! F I G. 8. 7 I6! I85 159 t i INVENTORS JAMES F. ARMSTRONG CHARLES K. MCONNELL ZMW MW ATTORNEY.

Oct. 31, 1961 J. F. ARMSTRONG ETAL 3,006,329

FUEL INJECTION SYSTEM Filed April 6. 1959 10 Sheets-Sheet 5 449 655 0 o 457\ O V I3: 7 57 O 6 9 s 66/ I c 409 o 25' NC I O 0 o v 0 o o C 4 445 429 O o o P O O 527 433 o 59 O l 0] O O O R/ 7 F l G. l2

INVENTORS JAMES F'. ARMSTRONG CHARLES K. MCONNELL i ATTORNEY 31, 1961 J. F. ARMSTRONG EI'AL 3,006,329

FUEL INJECTION SYSTEM 10 Sheets-Sheet 6 Filed April 6, 1959 ES F. ARMSTRONG JAM CHARLES K. MCONNELL BY v ATTORNEY Oct. 31, 1961 J. F. ARMSTRONG EIAL FUEL INJECTION SYSTEM Filed April 6, 1959 1O Sheets-Sheet '7 .2 JAMES F. ARMSTRONG CHARLES K. MCONNELL ATTORNEY Oct. 31, 1961 J. F. ARMSTRONG ETAL 3,006,329

FUEL INJECTION SYSTEM Filed April 6, 1959 10 Sheets-Sheet 8 F I G. l5.

N NC

F l-G. W.

F l G. I6

50/ NC 523 5o5/z y s 5/5 INVENTORS 5/3 JAMES F. ARMSTRONG N/ 5/! CHARLES K. MCONNELL P LM%W ATTORNEY Oct. 31, 1961 J. F. ARMSTRONG ETAL 3,006,329

FUEL INJECTION SYSTEM Filed April 6, 1959 10 Sheets-Sheet 9 INVENTORS JAMES F. ARMSTRONG CHARLES K. MCQNNELL ATTORNE Y Oct 31, 1 61 J. F. ARMSTRONG EIAL 3,006,329

FUEL INJECTION SYSTEM Filed April 6. 1959 10 Sheets-Sheet 10 gl i l i l hllh lN-VENTORS JAMES F. ARMSTRONG CHARLES K. M CONNELL HIORNEY A United States Patent Of 'ice 3,006,329 FUEL INJECTION SYSTEM James F. Armstrong, St. Louis, and Charles K. McConneli, Creve Coeur, Mo., assignors to ACE Industries, Incorporated, New York, N.Y., a corporation of New Jersey Filed Apr. 6, 1959, Ser. No. 894,518 38 Claims. ((11. 123-179) This invention relates to fuel injection systems for internal combustion engines, and more particularly to continuous flow systems of this class adapted for port injection, in which the fuel is pressurized, measured under pressure in accordance with engine requirements, and distributed under pressure to points adjacent the intake valves of the several cylinders or combustion chambers of the engine.

The invention is particularly concerned with a continnous-flow fuel injection system of a type having a fuel metering means for meter ng fuel to the engine in accordance with engine requirements as reflected by the rate of flow of air to the engine. This fuel metering means receives fuel from a source of fuel under pressure and delivers it to the engine at a rate proportional to the rate of flow of air to the engine. The metering means is of the variable-area orifice type, and the rate of flow therethrough is a function of orifice area and pressure differential upstream and downstream thereof. Provision is made for maintaining this pressure differential substantially constant, so that the rate of flow of fuel is substantially completely a function of orifice area. This is accomplished by providing pressure responsive nozzles fed by the metering means, and a datum pressure system for supplying control of datum pressure for controlling the nozzles. The datum pressure system receives fuel from the source and has a pressure regulator therein adapted to maintain a substantially constant differential between the source pressure and the datum pressure despite variations in the source pressure. In the operation of the fuel injection system, there is a continuous low rate flow of fuel from the source through the datum pressure system (including the datum pressure regulator). The fuel metering means is controlled by an air metering unit which functionsto measure the rate of air flow to the engine, and which is connected to the fuel metering means to vary the setting of the fuel metering means in relation to the rate of air flow.

In a fuel injection system of the class described, there is a problem of providing an increased rate of fuel delivery upon starting the engine under low engine temperature conditions and during warm-up of the engine, the rate being reduced as the engine warms up and ultimately reaching a normal value when the engine attains its operating temperature.

Accordingly, it is an object of this invention to provide an improved and simplified means for accomplishing such increase in the rate of fuel delivery for starting and engine warm-up, this being referred to as starting mixture enrichment.

In general, this object of the invention is attained by incorporating in the connection between the air metering unit and the fuel metering means, a means for varying the phase of the fuel metering means relative to the air metering unit in response to engine temperature, the arrangement being such that, for a given setting of the air 3,006,329 Patented Oct. 31, 1961 metering unit, the fuel metering means has a different setting when the engine is cold then when the engine is hot such as to provide for mixture enrichment when the engine is cold, the setting gradually changing as the engine warms up.

A further feature of the starting mixture enrichment means of this invention is that the temperature-responsive element thereof is provided in the fuel chamber of the fuel metering means (from Which chamber the fuel flows through the orifices of the fuel metering means to the engine) and the fuel in the fuel chamber is heated by the engine (as by a heat-exchange connection with the cooling system for the engine) so that the temperature of the fuel in the fuel chamber is a function of engine temperature. With this arrangement, there is a further advantage in that the fuel supplied to the engine is preheated, as is desirable.

Another problem in a fuel injection system of the class described is that of providing a temporary increase in the rate of fuel delivery upon sudden throttle opening (acceleration) to provide for mixture enrichment upon acceleration, as is desirable for certain engines.

Accordingly, it is an object of this invention to provide an improved mixture control for acceleration, adapted reliably to temporarily increase the rate of fuel delivery upon sudden throttle opening.

In general, this object of the invention is attained by providing means whereby, upon sudden throttle opening, the datum pressure is temporarily decreased, thereby allowing the fuel delivery nozzles to open wider for increased fuel delivery in conjunction with means for preventing the datum pressure from dropping below a predetermined minimum.

Other objects and features will be in part apparent and in part pointed out hereinafter.

The invention accordingly comprises the constructions hereinafter described, the scope of the invention being indicated in the following claims.

In the accompanying drawings, in which several of various possible embodiments of the invention are illustrated,

FIG. 1 is a schematic showing of a fuel injection system in which a starting mixture enrichment means of this invention is incorporated, illustrating various .parts of the system in the positions assumed when the engine is ofl;

FIG. 2 is a plan view, with parts broken away and shown in section, of an assembly of an air metering unit, a fuel metering chamber, and a datum pressure regulator of the FIG. 1 system;

FIG. 3 is a view in elevation of one side of the FIG. 2 assembly;

FIG. 4 is a view in elevation of the opposite side of the FIG. 2 assembly;

FIG. 5 is a plan view of the engine intake manifold;

FIG. 6 is a vertical section taken on line 6-6 of FIG. 5;

FIG. 7 is a vertical section of a nozzle of the FIG. 1 system taken on line 7-7 of FIG. 5;

FIG. 8 is a greatly enlarged fragment of FIG. 7;

FIG. 9 is a section of a datum pressure regulator of the FIG. 1 system taken on line 99 of FIG. 2;

FIG. 10 is a section taken on line 10-10 of FIG. 9;

FIG. 11 is a section taken on line 11 of FIG. 9;

FIG. 12 is a plan view of an engine equipped with a fuel injection system in which both a starting mixture enrichment means and a mixture control for acceleration of this invention are incorporated;

FIG. 13 is a front end view of the engine shown in FIG. 12;

FIG. 14 is a schematic showing of the FIG. 12 system;

FIG. 15 is a vertical transverse cross section of the engine taken on line 1515 of FIG. 12;

FIG. 16 is an enlarged vertical transverse section taken on line 1616 of FIG. 12;

FIG. 17 is a cross section of an equalizer valve of the FIG. 12 system;

FIG. 18 is a cross section of a datum pressure regulator of the FIG. 12 system;

FIG. 19 is a View in elevation of the datum pressure egulator as viewed from the right of FIG. 18, with parts broken away and shown in section;

FIG. 20 is a cross section of a combination bleedoflf and datum pressure relief unit of the FIG. 12 system;

FIG. 21 is a cross section of a differential pressure limiter or minimum datum pressure control of the FIG. 12 system;

FIG. '22 is a view in elevation illustrating a specific construction for varying the phase of the fuel metering means relative to the air metering unit in response to engine temperature; and,

FIG. 23 is a wiring diagram.

Corresponding reference characters indicate corresponding parts throughout the several views of the drawlllgS.

General description of the Fig. 1 system Referring to FIG. 1 of the drawings, a fuel injection system in which a starting mixture enrichment means of this invention is incorporated is shown to comprise an air metering unit A for metering air to an engine E, and a fuel charging or delivery system F for delivering fuel to the engine at a metered rate with the proportion of air to fuel (the air-fuel ratio) appropriate to the operating requirements of the engine Whatever they may be. The air metering unit A comprises a cylindrical conduit 1 with a uring the rate of air flow through conduit 1 to the intake manifold M of the engine, conduit 1 being connected to the manifold in any suitable manner.

The fuel delivery system F delivers fuel to the engine from a fuel metering chamber C which is supplied with fuel under pressure from the fuel tank 9 of the vehicle. An electric pump -11 is provided in the tank for continuously pumping fuel through a fuel line 13 to the chamber C when the engine is in operation. In line 13 is a check valve 15 for preventing flow of fuel back toward the pump. Chamber C has a plurality of outlet passages such as indicated at 17. As herein described, engine E is a V-8 engine, and eight outlet passages 17, one for each cylinder of the engine, are provided, but it will be understood that alternative arrangements in which one passage and nozzle N serves more than one cylinder may be used, as in the case of a Siamese inlet port. Fuel is adapted to flow from chamber C into each of passages 17 through an orifice 19 under control of a contoured (tapered) metering rod 21 (one for each passage 17). Themetering rods 21 (eight in this instance) are all carried by a crosshead 23 for simultaneous equal movement inward and outward with respect to the orifices. Crosshead 23 is controlled by the air valve 7. The rate of flow of fuel through each orifice is a function of the position of the metering rod therefor (which establishes the effective area of the orifice) and the pressure drop across the orifice, i.e., the difference between the pressure of fuel in chamber C and the pressure downstream from the orifice. Hence, the rate of flow of fuel is a function of the rate of air flow through the air metering unit A and the pressure drop across the orifices.

Associated with each cylinder of engine E is a nozzle N adapted to inject fuel close to and in the direction of the intake valve for the cylinder. Fuel delivery lines such as indicated at 25 connect outlet passages 17 of chamber C to the respective nozzles N. There are eight nozzles N and eight fuel lines 25. Each nozzle N comprises a needle 27 attached to a diaphragm (see FIG. 7), whose movement is responsive to a pressure differential between the pressure of fuel supplied to the nozzle N through the line 25 on one side of diaphragm 135 and the pressure in a datum pressure system D supplying fuel to the other side of diaphragm 135. The pressure in lines 25, and hence the pressure drop across orifices 19, is dependent upon the position of the needles 27. The datum pressure system D utilizes fuel from the chamber C as a datum pressure medium. As illustrated in FIG. 1, the datum pressure system D comprises a line 29 leading from chamber C to a T 30, from which branch lines 31 and 33 pass around both sides of the manifold M, these branch lines being connected to the datum pressure chambers 139 of the two nozzles at one end of the engine.

The datum pressure chambers of the nozzles on one side of the manifold are interconnected by lines such as indicated at 31a and the datum pressure chambers 139 of the nozzles at tr e other side of the manifold are interconnected by lines such as indicated at 33a. Lines 31b and 33b lead from the datum pressure chambers 139 of the two nozzles at the other end of the engine to a T 35. Line 37 leads from T 35 to a datum pressure regulator R. From this pressure regulator R there is a passage 39 to the inlet of a solenoid valve 40 and a return line 41 from the outlet of the solenoid valve to the fuel tank 9. The solenoid valve, when de-energized, cuts OK the return. Lines 29, 3 1, 33, 31a, 31b, 33a, 33b, 37, passage 39, and return 41, constitute a by-pass around the pump 11.

Regulator R is interconnected with chamber C as indicated at 43. As will be made clear, regulator R functions to maintain a substantially constant pressure drop across orifices 19, despite variations in fuel pressure in chamber C, so that the rate of flow of fuel through nozzles N is dependent substantially entirely upon the position of the metering rods 21, hence dependent upon the rate of air flow through air metering unit A. Regulator R also acts in response to opening of the throttle, as will be made clear, to reduce the datum pressure to deliver additional fuel through nozzles N for acceleration and, conversely, acts in response to release of the throttle to raise the datum pressure and reduce or cut ofi the flow of fuel through nozzles N to obtain satisfactory engine operation when decelerating with a closed throttle. In normal operation, fuel flows continuously at a low rate in the datum pressure system from chamber C through the datum pressure chambers 139 of nozzles N to the regulator R, and from the regulator R back to the fuel tank 9. This tends to keep the system purged of air and accumulated vapors. The low rate of fiow is established by restrictions 44 in branch lines 31 and 33 upstream from nozzles N. It is emphasized that restrictions 44 are upstream and the regulator R is downstream from the nozzles. This is an important feature of the invention.

Incorporated in the fuel injection system of this invention is a starting mixture enrichment system generally indicated at S. As will be made clear, this system acts to vary the phase of the metering rods 21 relative to the air measuring valve 7 in such manner as to provide for mixture enrichment when the engine is cold, bringing the metering rods to a normal phase position relative to valve 7 as the engine warms up. A fast idle control such as indicated at P1 is provided. The electrical components of the system are connected in an electrical circuit generally indicated at EC, this circuit including a throttle operated unloading switch U for clearing the engine of excess fuel when necessary.

1 he air metering unit The throttle valve 3 is fixed on a throttle shaft 45 extending across the conduit 1 adjacent its exit end (its lower end as viewed in FIGS. 1 and 3). At this end of the conduit 1 is a flange 47 whereby it may be attached to the intake manifold of the engine. As appears in FIG. 1, the throttle valve is manually operated by the usual accelerator pedal 49 of the vehicle, being biased toward closed position by a return spring 51. The air valve 7 is a balanced butterfly valve, fixed on a shaft 53 extending across the conduit 1 parallel to and upstream from the throttle valve shaft 45. The space in conduit 1 between the shafts 45 and 53 is divided by a slotted partition 55 extending lengthwise of the conduit in the plane of the shafts. On the conduit 1 is a servo-motor 57 for actuating the air valve 7. This servomotor comprises a casing divided into an inner chamber 61 and an outer chamber 63 by a diaphragm 65. Air valve 7 has an upwardly extending bracket 67 which is connected by a link 69 to the diaphragm, the link extending through a hole 71 in the wall of conduit 1. A spring 73 in the outer chamber 63 of the servo-motor biases the diaphragm in the direction to close the air valve 7. A Pitot tube 75 has one end reaching into conduit 1 on one side of the partition 55 and its other end connected to the outer chamber 63 of the servo-motor. The air valve 7 has a deflector or spoiler 77 on its under side at its leading edge. The air valve 7 is also provided with a spring loaded relief valve 78 on its upstream side. It will be observed that the diaphragm is subject substantially to atmospheric pressure on its side toward chamber 61 (open via hole 71) and, when the throttle valve is opened, to a lower pressure on its side toward chamber 63 due to the Pitot tube. The pressure ditferential causes the air valve 7 to open against the bias of the spring 73. The amount of opening is proportional to the pressure differential, hence proportional to the rate of air flow.

Mounted on the conduit 1 is a vacuum operated air bleed motor 79, which may be referred to as an economizer, for modulating the action of servo-motor 57 to provide a leaner mixture in the part throttle range than in the full throttle range. Motor 79 comprises a casing divided by a diaphragm 81 into two chambers 83 and 85. In chamber 83 diaphragm 81 carries a valve 87 adapted to engage a valve seat at the entrance to a tube 89 which connects chamber 83 and the outer chamber 63 of the servo-motor 57. There is a restriction 91 at the entrance of tube 89. A spring 93 in chamber 85 biases the diaphragm in the direction to move valve 87 to closed position engaging its seat and blocking tube 89. Chamber 83 is connected as indicated at 95 with a port 97 in the wall of conduit 1 located upstream from the leading edge of the air valve 7. Chamber 85 is connected as indicated at 99 with a port 161 in the wall of conduit 1 located adjacent the edge of the throttle upstream from the position of the leading edge of the throttle valve 3 when the latter is closed to the idle range. This arrangement provides for more effective range of mixture control by the idle mixture screw 165. In the part throttle range of operation, port 97 is upstream from the air valve 7 and port 101 is downstream of the opening edge of the throttle valve 3. Diaphragm 81 then holds valve 87 open so that a restricted amount of air bleeds from the port 97 through chamber 83 and tube 89 to the chamber 63 of the servomotor 57 to modulate the suction in chamber 63 caused by the Pitot tube 75. This reduces the amount of opening of the air valve 7 that will otherwise be caused, and has the effect of reducing the rate of flow of fuel to provide a proper mixture for part throttle road load operation. In

the nearly full throttle range of operation, however, both ports 97 and 101 are downstream from the air valve 7 and throttle valve 3, respectively. A relatively high vaccum is thereupon drawn in chamber 83 of the economizer 79, with the result of reducing the bleeding of air to the servo-motor 57 thereby eliminating or substantially eliminating the eifect of the economizer on the servomotor. In the wide open throttle position, due to the small difierence in pressure between 101 and 97, spring 93 is sufficiently strong to position valve 87 firmly on its seat, and cut off the bleed action to the chamber 63.

The conduit 1 has an air by-pass passage 103 which extends around the edge of the air valve 7 when the latter is in a nearly closed position. Flow of air through this by-pass is controlled by a metering screw 105. By adjustrnent of this screw, it is possible to vary the position of the air valve 7, and hence metering rods 21, etc., in the low range of engine speeds (in the idle range and slightly above). This provides a fuel mixture control in the low range of engine speeds. When air valve 7 opens beyond the upper port to this passage, the by-pass is out of operation. Conduit 1 also has an air by-pass 107 extending around throttle valve 3. Flow of air through this by-pass is controlled by a metering screw 109. This by-pass provides for flow of air for idling around the throttle valve when the latter is closed, the flow being adjustable by means of screw 109' to control the engine idling speed. Throttle valve 3 is provided with a thermostatic strip 110 covering opening 112 in the valve. When the air passing through conduit 1 reaches a predetermined temperature range, opening 112 is uncovered to permit a small portion of the air to pass through the throttle valve.

The fuel metering chamber As appears in FIG. 2, the fuel metering chamber C is associated with the conduit 1, comprising a casing 111 which may be formed as an integral part on conduit 1 and a closure plate 113 for the casing. Casing 111 is located on the side of conduit 1 at one end of the air valve shaft 53. At this end of the air valve shaft 53, conduit 1 has a recess 115 accommodating a magnet coupling member 117 fixed on the end of the air valve shaft. A thin plate 119 of nonmagnetic material closes this recess, sealing 01f chamber C from the recess. The magnetic coupling member 117 is active upon a driven magnetic coupling member 121 in the chamber C rotatable on a stud 123 carried by plate 119. A lever 125 is pivoted on the stud 123 and coupled to the driven magnetic coupling member 121 by a thermostatic member 127 (FIG. 1). This thermostatic member constitutes an element or" the starting mixture enrichment system S, as will be made clear. For the time being, the lever 125 and coupling member 121 may be regarded as locked together. A link 129 connects the lever and the crosshead 23 which carries the metering rods 21. The arrangement is such that, upon rotation of the air valve 7 and the air valve shaft 53, the driven magnetic coupling member 121 rotates in unison with the driving magnetic coupling member 117 on air valve shaft 53 to move the crosshead 23 and the metering rods 21 in amount proportional to the rotation of the air valve 7. Magnetic coupling members 117 and 121 provide a friction-free leakproof connection for transmitting the torque developed by the air valve 7 to the metering rods 21 to move them in proportion to the rotation of the air valve, and in direction corresponding to the direction of rotation of the air valve. Reference has already been made to the outlet passages 17 and orifices 19 of the fuel metering chamber C.

The nozzles As appears in FlG. 5, the injector nozzles N are clustered in groups of two, so that, as a matter of practice, there are four nozzles clusters on the intake manifold M of the engine. Eight individual nozzles N appear needle enlargement 171.

in the diagrammatic representationof FIG. 1 for simplicity of illustration. As shown, each nozzle cluster comprises a body 131 formed to provide two shallow circular recesses 133 located side-by-side. these recesses appears in FIG. 7. A diaphragm 135 is clamped on the body by a head 137. This head is similarly formed to provide two shallowcircular recesses 139 located side-by-side, which mate with recesses 133. Again, only one of these recesses 139 appears in FIG. 7. As to each nozzle N, recess 133 constitutes a charging fuel chamber and recess 139 constitutes a datum pressure chamber. The head 137 has an internally recessed rib 141 extending lengthwise thereof. This provides a passage 143 connecting the two datum pressure chambers of thecluster. Fuel connections may be made between the ends of these ribs to provide for the interconnection of the datum pressure chambers of all the nozzles N in the system (corresponding to the connections such as indicated at 31, 31a, 31b, 33, 33a and 33b in FIG. 1). FIG. shows interconnections at 145 between the forward and rearward clusters of each bank of four cylinders of the engine. The body 131 and head 137 are formed with bolt holes 147 for the reception of bolts for attaching them to the manifoldM.

For each of the two nozzles N in a cluster, the base 131 of the cluster has an outwardly (downwardly) projecting tubular boss 149 coaxial with the recesses or chambers 133, 139. The hole through this boss is enlarged at its inner end providing a recess 151 and an inwardly facing annular shoulder 153. Each nozzle N comprises a nozzle tube 155 threaded in the hole in the boss and projecting out (downward) from the boss. The nozzle tube has a head 157 at its inner (upper) end received in the recess 151 and seating against shoulder 153 for sealing purposes. Fixed in the outer (lower) end of the nozzle tube is a combination nozzle tip and valve seat member 159. This comprises a short tube having an annular external flange 161 which is press fitted into the inturned flange 163 at the outer (lower) end of the nozzle tube 155. The outer end of tip 159 is cut off at an angle as indicated at 165. The inner end portion of the tip 159 extends inward from flange 161 and provides a needle seat 167 Each nozzle N includes the needle 27 having its inner (upper) end attached to the diaphragm 135, the needle extending slidably in the nozzle tube 155. The diameter of the needle is less than the internal diameter of the nozzle tube, to provide an annular space around the needle for flow of fuel through the tube to tip 159,'and the needle is held centered in the tube by upper and lower radial projections 169 on the needle which slide on the internal surface of the nozzle tube. At its outer (lower) end, the needle has an enlarged portion 171. This portion has a conically concave face 173 at its outer end. It also has an axial passage 175 leading inward from the face and a passage 177 extending radially outward from the upper end of passage 175. Seated against face 173 Is a piece of Wire mesh 179, and seated against the wire mesh is a disk 181 of fuel-resistant rubber or the like.

The wire mesh 179 and rubber disk 181 are held against the face 173 by a cap 183 press fitted on the The cap has an opening 185 for receiving the inner end portion 167 of nozzle tip 159. The cap terminates short of the radial passage 177, this passage and passage 175 being provided to vent air from under the disk 181 in the assembly of the Wire mesh, disk and cap on the needle enlargement 171. The rubber disk 181 is initially a flat disk held in a bowed condition under compression against the face 173 by the cap 183, which places the lower working surface under compression to constitute a resilient tip for the needle engageable with the inner end 167 of the nozzle tip (which oonstitutes a seat for the needle) to provide a tight seal to prevent leakage when the needle is closed. The rubber face. of the valve, being compressed, resists the shearing Only one of forces of seat engagement. The screen is used to provide for some slight swelling of the rubber composition between the interstices thereof. With the arrangement shown, when the needle is retracted and the rubber disk is clear of the seat 167, fuel flows upward around the seat 167, and thence around into the nozzle tip and down and out of the nozzle tip. This tends to avoid the formation of droplets at low rates of flow as during engine indling which would cause engine idle roughness.

As to each nozzle N, the needle 27 is biased downward by a spring 187 toward its closed position wherein the rubber disk 181 at the lower end of the needle engages the needle seat 167. For each nozzle, there is a passage 189 through the base and the head communicating with the lower recess or chamber 133. To this passage is connected the respective fuel delivery line 25. Accordingly, the needle 27 is subject to the downward force of spring 187 and datum pressure in recess or chamber 139 tending to drive it downward and close it, and an upward force due to char ing fuel pressure in the lower recess or chamber 133 tending to drive it upward and open it. The charging pressure being sufficient to overcome the force of the spring 187 and the datum pressure, diaphragm is moved upward to unseat the needle 27 from needle seat 167 for flow of fuel from chamber 133 out of the nozzle. Upon an increase in datum pressure, diaphragm 135 flexes downward to move the needle 27 closer to its seat 167, thereby to increase the back pressure in the nozzle charging fuel chamber 133, and vice versa.

The datum pressure regulator As appears in FIGS. 2 and 3, the datum pressure regulator R is associated with the fuel metering chamber C, being connected thereto by the connection or fitting 4-3. The regulator is formed to provide first, second and third expansible chambers 191, 193 and 195 in tandem (see P168. 9 and 11). The first chamber 191, 'which is the bottom chamber of the three, is provided by a cup-shaped base 197 closed at the top by a diaphragm 199 clamped against the rim of the base by a ring 291. The second or intermediate chamber 193 is constituted by the space within the ring 261, being closed at the bottom by diaphragm 199, and at the top by a second diaphragm 203, the latter being clamped against the top of the ring by a head 265. The third or upper chamber 195 is constituted by a recess in the bottom of the head, closed at the bottom by the second diaphragm 203. The head overhangs the base and ring, and carries the solenoid valve 40.

Return passage 39 is formed as a horizontal passage in the head 295 extending from an outlet 207 coaxial with the two diaphragms to a recess 209 extending upward from the bottom of the overhanging portion of the head. The head is formed with a valve seat 211 for the solenoid valve which extends downward in the recess 209. The solenoid of the valve 49 is in a case 212 having a neck 213 threaded in the recess 2199. The plunger 215 of the solenoid has a resilient valve member 217 at its upper end engageable with the valve seat 211 when the solenoid is de-energized to cut off flow through an outlet passage 219 provided in the head extending through the valve seat. The plunger is biased by a spring 229 (see FIG. 1) in the direction (upward as viewed in FIGS. 9 and 10) for engagement of valve member 217 With seat 211. When the solenoid is energized, the valve member is Withdrawn from the seat. The outer end of the outlet passage 219 is threaded as indicated at 221 in FIG. 10 for connection of the aforementioned fuel return line 41 leading back to the fuel tank 9. The head 205 has a threaded lateral inlet port 223 (see FIG. 11) for connection of the aforementioned datum line 37, this port leading into the upper regulator chamber 195. At its outer end, the head has a threaded port 225 leading to recess 209 for connection of a vapor vent line 227 (see FIG. 1) leading from fuel metering chamber C for carrying oif vapor from chamber C when the solenoid valve 40 is open.

. A tubular valveguide and seat member 229 (FIGS. 9-

ll) has a reduced upper end portion threaded in the outlet 207, and extends downward in the upper regulator chamber 195. The upper diaphragm 203 carries a cup 231. A needle valve 233 has its lower end secured to the bottom of the cup 231 and extends upward in member 229, being slidable therein. A spring 235 surrounding member 229 biases the upper diaphragm 203 and needle valve 233 downward in the opening direction. The needle valve 233 is thus subject to the downward force of spring 235 and pressure in the upper regulator chamber 195 tending to open it, and to the pressure in the intermediate regulator chamber 193 tending to close it. The lower diaphragm 199 is biased downward by a spring 237 reacting from an internal shoulder 239 formed in the ring 291. A fluted guide pin 241 has its upper end fixed to the center of the lower diaphragm 199 and extends downward in a tubular guide 243 which is threaded in the bottom of the cup-shaped regulator base 197. The guide pin 241 is slidable in the tubular guide 243. A bushing 245 is threaded in an opening 247 in the annular wall of the cup-shaped regulator base 197 with its axis parallel to the axis of the throttle shaft 45. A shaft 249 is rotatable in the bushing (F168. 4 and 11). Packing to prevent leakage around the shaft is indicated at 251, and this is a plastic washer having a low coefiicient of friction (Teflon) placed against the movable surface, and a plastic washer (rubber) placed against the stationary surface. At its inner end in the lower regulator chamber, shaft 249 carries a cam 253 (FIGS. 9 and 11) engageable by a wear plate 255 on the underside of the lower diaphragm 199. An arm 257 is fixed to the outer end of the shaft 249. A link 259 connects this arm to an am 261 on the throttle shaft (FIGS. 24). The arrangement is such that when the throttle valve 3 is closed, cam 253 occupies a position holding the lower diaphragm 199 in a raised position. When the throttle valve 3 is opened, cam 253 is rotated clockwise as viewed in FIG. 9, allowing the lower diaphragm 199 to flex downward. A spring 262, a torsion spring in compression, is provided for biasing the shaft 249 and cam 253 to rotate counterclockwise toward the raised-diaphragm position of the cam, and to provide for keeping the seal 251 under compression. This dual function eliminates sliding friction between the parts. The ring 201 has a radial nipple 263 which is externally threaded for reception of a coupling nut 265 to couple the regulator to the fitting 43. The nipple 263 has a horizontal passage 267 receiving fuel from chamber C via fitting 43. From the inner end of this horizontal passage there is a port having a restriction 269 leading into the intermediate regulator chamber '193. There is also a downwardly extending opening 271 communicating with a passage 273 formed in the annular wall of the cup-shaped regulator base 197 communicating with the lower regulator chamber 191. Thus, the lower and intermediate regulator chambers 191 and 193 are in communication with the fuel metering chamber C, with communication to the intermediate chamber 193 restricted at 269.

The starting mixture enrichment system The starting mixture enrichment system S comprises tne aforementioned thermostatic member 127 and a heatexchange pipe 275 for circulating coolant (water) from the cooling system 277 of engine E through the fuel metering chamber C. The radiator of the cooling system is indicated at 279. in FIG. 1, and the pump for circulating coolant is indicated at 281. The closure plate 113 of chamber C has an inlet port 283 (FIG. 3) to which is connected a pipe 285 leading from the cooling system 277 on the outlet side of pump 281. Pipe 275 extends in chamber C through a tortuous course from inlet port 283 to an outlet port 287 in closure plate 113. The outlet port 237 opens into a valve housing 289 mounted on the closure plate 113. This housing 289 has an outlet port 291 to which is connected a return pipe 293 leading back to the cooling system on the inlet side of the pump 281. In the housing 289 is a. thermostatic valve 295 which, when cold, is bent away from port 291 and which, as it is heated by the coolant (which becomes hotter and hotter as the engine warms up) bends toward port 291, ultimately closing off the latter when the engine has reached operating temperature to reduce the circulation of coolant through the heat-exchange pipe 275 and maintain an even fuel temperature in chamber 111.

When the engine is cold, the coolant is cold and the fuel in chamber C is cold. Accordingly, the thermostatic member 127 is cold. When this thermostatic member is cold, it holds the lever at a certain angle relative to the magnetic coupling member 121. As the engine warms up, the coolant warms up. Due to the circulation of the warmed up coolant through the heat-exchange pipe 275 in chamber C, the fuel in chamber C is heated and the thermostatic member 127 is heated. As the thermostatic member 127 is heated, its shape changes in such a way as to change the angle of lever 125 .relative to coupling member 121. Since the lever 125 controls the position of crosshead 23 and metering rods 21, the heating of the thermostatic member 127 results in a change in the position of the metering rods. The arrangement is such that, for a given position of the coupling member 121 (such as the position it assumes at idle), the metering rods 21 occupy a more drawn-out position when the engine is cold than they occupy when the engine is warm, thereby providing for mixture enrichment when the engine is cold. This also would be true at any rate of air flow and engine speed.

The fast idle control The fast idle control FI (FIG. 4) comprises a fast idle cam 297 pivoted at 299 on the conduit 1. This cam is controlled by a thermostatic'member 301 in a housing 303. The thermostatic member is responsive to engine temperature. Ann 261 on the throttle shaft 45 carries a screw 305 engageable With the cam to determine the throttle opening at idle in accordance with the position of the cam as determined by engine temperature.

The electrical circuit and unloader At 307 (FIG. 1) is indicated the battery of the vehicle. One terminal of the battery is grounded as indicated at 309. A line 311 extends from the other terminal of the battery to one terminal of starting switch 313. A line 315 extends from the other terminal of the starting switch to one terminal of the starting motor 317 for engine E, the other terminal of the motor being grounded as indicated at 319. A line 321 including ignition switch 323 extends from line 311 to one terminal of a normally closed relay 325. The coil of the relay is connected in a line 327 extending from one terminal of the unloader switch U to line 315. The other terminal of the unloader switch is grounded as indicated at 329. The unloader switch U is normally open, being closed when the accelerator pedal 49'is pushed to open the throttle valve 3 wide. A line 331 extends fromthe other terminal of relay 325 to one terminal of an oil pressure switch 333. This switch is normally open, being closed by engine oil pressure when the engine is in operation. A line 335 extends from the other terminal of the oil pressure switch to the solenoid 42 of solenoid valve 40, which is grounded as indicated at 337. Another line 339 extends from the other terminal of the oil pressure switch to the motor of the electric fuel pump 11, which is grounded as indicated at 341.

Operation To start the engine E, ignition switch 323 is closed and starting switch 313 is closed to energize the starting motor 317 to crank the engine E. Relay 325 being normally closed as appears in FIG. 1, and oil pressure being developed to close the oil pressure switch 333, the electric pump 11 is energized to pump fuel to fuel metering the same.

chamber C and solenoid valve 49 is energized to open. 7

' datum pressure chambers 139 of nozzles N and the upper,

. differential may be about /2 psi, for example, and it is maintained except during rotation of the cam 253, at which times it is reduced or raised (depending upon which way the cam rotates), as will be made clear. The regulator R acts in accordance with variations in the pressure in chamber C to maintain the stated pressure differential as follows: Upon a decrease in charging pressure in chamber C, the pressure in regulator chambers 191 and 193 drops. Diaphragm 203 thereupon moves downward to move the regulator valve 233 farther away from its seat. This allows fuel to escape more readily from chamber 195 and datum line 37 so as to drop the datum pressure an amount equal to the drop in charging pressure, whereby the difference between charging pressure and datum pressure remains the same. Upon an increase in charging pressure in chamber C, the pressure in regulator chambers 191 and 193 increases. Diaphragm 203 thereupon moves upward to move the valve 233 closer to its seat. This increases the datum pressure an amount equal to the in creasein charging pressure so that the difference between charging pressure and datum pressure remains Thus, the regulator R reduces the charging pressure by a predetermined amount (V2 p.s.i., for example) to convert it to datum pressure.

As to each nozzle N, the nozzle diaphragm 135 is subject on one side totcharging pressure in chamber 133 tend ing to move the nozzle needle 27 away from its seat 167, and subject on the other side to datum pressure in chamber 139 and to force of the nozzle spring 187 tending to move the nozzle needle toward itsseat. With the charging pressure high enough to overcome the closing force on the nozzle needle 27 due to the datum pressure and spring 187, the needle is unseated, and fuel is discharged-through the tip 159 of the nozzle. The rate, of

how of fuel through a nozzle is dependent upon the position of the metering rod 21 related to that particular nozzle in relation to the metering rod orifice 19 and the pressure drop acrossthe orifice. As long as the pressure differential between charging pressure and datum pressure remains substantially constant, the pressure drop across orifice 19 remains substantially constant, being equal to the stated pressure differential plus the pressure created by the nozzle spring 187 (which is a low rate spring). Thus, the pressure drop across orifice 19 is normally maintained substantially constant, and variations in the rate of flow. of charging fuel are caused solely by moving the metering rods 21 in or out, the farther in the rods, the lowerthe rate of flow, and vice versa.

ing fuel at a minimum rate corresponding to the rate of flow of air to the engine. As the air valve 7 opens with increase in the rate of air flow, the metering rods 21 are 'withdrawn an amount proportional to the opening of the air Valve to increase the rate of flow of charging fuel proportionately to the increase in the rate of air flow. In the part throttle range, the opening'of the-air valve 7 is attenuated by the economizer 79' to attenuate the withdrawal of the metering rods to provide a lower rate of flow of charging fuel than would occur without such attenuation, so as to deliver an economy mixture of air and fuel to the engine. In the full throttle range of operation, wherein the air valve 7 has opened to the point where port 97 is downstream from the air valve, the attenuating effect of the economizer 79 is decreased, and the metering rods 21 are withdrawn to the point of providing the necessary rate of flow of charging fuel in relation to the rate of flow of air to deliver a richer mixture. A full rich mixture for power is delivered when manifold pressure increases to close valve 87.

On starting a cold engine, valve 87 is closed to provide a richer mixture, and during starting and engine warm-up, the thermostatic member 127 functions to provide for enrichment of the mixture by changing the phase of the metering rods 21 relative to the magnetic coupling member 121 and the air valve 7. As the engine warms up, the modulation of metering rod position by the thermostatic member 127 is lessened, and, once the engine has fully warmed up, the thermostatic member has no further effect.

On acceleration (pushing down the pedal 49) cam 253 is rotated clockwise as viewed in FIG. 9. The lower diaphragm 199 of regulator R is subject on both sides to charging pressure (regulator chambers 191 and 193 being in communication with fuel metering chamber C) and additionally subject to the downward force of spring 237. Accordingly, spring 237 drives the lower diaphragm 199 downward, forcing fuel out of chamber 191. Restriction 269 acts momentarily to prevent the fuel forced out of chamber 191 from entering chamber 193, most of the fuel being forced back to chamber C and increasing the pressure in chamber C. The pressure in the intermediate regulator chamber 193 is lowered, and the upper regulator diaphragm 203 is driven downward. This pulls valve 233 farther away from its seat, thereby reducing the datum pressure. Upon the drop in datum pressure in the nozzle datum pressure chambers 139, the nozzle diaphragms 135 respond to move the nozzle needles 27 farther away from their seats. This drops the pressure in the charging fuel chambers 133 of the nozzles. Thus, the pressure drop across metering orifices 19 is increased. As a result of this increase in the pressure drop across the orifices, charging fuel is delivered at a higher rate than it otherwise would have been delivered. This provides for momentary mixture enrichment on acceleration. The action on deceleration is the reverse, cam 253 then rotating countercloclo wise and driving the lower regulator diaphragm 199 upward. Because of restriction 269, this results in increase of pressure in chamber 193, and the upper regulator dia- V phragm 293 moves upward to move the regulator valve The position of the metering rods 21. is dependent upon the position of air valve 7 and the temperature of thermostatic member 127. The position of the air valve is dependent upon the rate of air flow through the conduit 1. The temperature of thermostatic member 127 is dependent upon the temperature of engine E. Assuming that the engine is fully warmed, up, the effect of tcmperatureon the position of the rods may be disregarded, and it will be observed that with the air valve 7 closed, the metering rods 21 will occupy an advanced position wherein the effective area of each orifice 19 (the annular area around the rod within the orifice) is a minimum, for flow of charg- 233 nearer its seat. This increases the datum pressure, and the nozzle .diaphragms respond to move the nozzle needles 27 closer to their seats. This decreases the rate of delivery of charging fuel. When the cam 253 comes to rest after the accelerating or decelerating movement of the pedal 49, the pressure on opposite sides of the lower regulator diaphragm 199 equalizes, no matter what position the cam 253 may be in, and the equilibrium of the regulator R is restored so that it resumes functioning to maintain the substantially constant pressure differential between charging and datum pressure.

For unloading (i.e., clearing the engine of excess fuel), the pedal 49 is pushed all the way in, thereby closing the unloader switch U. This completes a circuit for the coil of relay 325, and the latter opens. This deenergizes the electric pump 11 and the solenoid valve 4%. The

valve 217 closes, thereby holding pressure in the datum system. With the pump cut off and increased pressure in the datum system, nozzles N close to cut off delivery of charging fuel to the engine. The engine is cranked by closing the starting switch 313, and this clears the engine of excess fuel.

If heat should cause expansion of fuel in the datum system with resultant increase of pressure in the datum system, the pressure drives the upper regulator diaphragm 203 downward, thereby opening up the regulator valve 233 to relieve the excess pressure via passage 39 and return line 41 (the solenoid valve 40 being open). It will be observed that with solenoid valve 40 open, there is no restriction in the datum system downstream from the regulator R such as would inhibit relief of excess pressure.

General description of the FIG. 12 system Referring to FIGS. 12 and 14 of the drawings, a sec ond fuel injection system, in which is incorporated both the starting mixture enrichment means and the mixture control for acceleration of this invention, is again shown to comprise an air metering unit A for metering air to engine E, and a fuel charging or delivery system F1 for delivering fuel to the engine at a metered rate with the proportion of air to fuel (the air-fuel ratio) appropriate to the operating requirements of the engine whatever they may be.

The fuel delivery system F1 delivers fuel to the engine from fuel metering chamber C. Fuel is supplied to the chamber C from fuel tank 9 of the vehicle by means of a mechanical fuel pump 401. Fuel feeds from the tank through line 13av/hich includes a fuel filter 403. The pump 401 is driven by the engine E. At 405 is indicated a fuel heater, comprising a fuel tube 407 in a Water jacket 409; A fuel line 13b extends from the outlet of pump 401 to a connection at 411 with one end of the fuel tube 407. A fuel line 130 extends from a connection at 413 with the other end of the fuel tube 407 to the stem of a T 415. A fuel line 13d extends from one end of the head of the T 415 to the fuel chamber C. Coolant (Water) from the cooling system 277 of engine E is circulated through the jacket 409 around the fuel tube 407. For this purpose, a hose line 417 is connected to one end of the jacket 409 from the outlet side of the coolant-circulating pump 281, and a coolant return hose line 419 leads from the other end of the jacket to the return side of the coolant-circulating pump. Lines 421 and 423 shown in FIG. 12 only are supply and return lines for the usual car heater. The arrangement is such that fuel delivered by the mechanical pump 401 is heated as it flows through tube 407 within jacket 409 by heat exchange with engine-heated coolant flowing through the jacket. Thus, the fuel is preheated as it is delivered to fuel chamber C, and its temperature, being dependent upon the temperature of the coolant for the engine, is dependent upon engine temperature.

In the FIG. 12 system, engine E is again shown as a V8 engine, and associated with each of the eight cylinders of the engine is a nozzle N1 (see FIGS. 15 and 16) adapted to inject fuel close to and in the direction of the intake valve 425 (see FIG. 12)' for the cylinder. Fuelv chamber C has eight outlet passages 17 (like chamber C of FIG. 1) and there are eight fuel delivery lines 25 (see FIGS. 12-14) connecting these outlet passages to the respective nozzles. As in the FIG. 1 system, each nozzle N1 comprises a needle responsive to the pressure differential between fuel supplied thereto through the respective line 25 and the pressure in a datum pressure system, which is designated D1 in FIGS. 1214.

The datum pressure system D1 of FIGS. 12-14 comprises a line 427 leading from chamber C to one end of the head of a T 429. The stem of this T is connected to the inlet of a solenoid valve 431 which is referred to as an equalizer valve. A line 433 leads from the other end of the head of the T to the inlet of a datum pressure regulator R1. A line 441 connected to the outlet of the regulator R1 supplies datum pressure to the datum pressure chambers of the four nozzles N1 for the four cylinders on one side of the engine. A line 443 also connected to the outlet of regulator R1 supplies datum pressure to the datum pressure chambers of the four nozzles N1 for the four cylinders at the other side of the engine. Regulator R1, as will be made clear, is adapted to maintain a substantially constant pressure differential between chamber pressure and datum pressure, the datum pressure being lower than chamber pressure. A line 445 leads from the outlet of the equalizer valve 431 into the datum pressure system. When the solenoid of the equalizer valve is energized, the valve is closed to block flow of fuel through line 445 into the datum pressure system. When the solenoid of the equalizer valve is deenergized, fuel at chamber pressure is delivered directly into the datum pressure system via line 445, thereby to equalize datum pressure and chamber pressure so as to close 01f nozzles N1.

In normal operation of the system, fuel flows continuously at a low rate in the datum pressure system from chamber C through the datum pressure regulator R1, thence through the datum pressure chambers of nozzles N1, thence through a datum bleed-off regulator 449 and a return line 451 which leads back to the tank 9. This regulator 449 includes a restriction and a valve for limiting the return flow and maintaining a predetermined min imum pressure in the datum system. A by-pass 455 controlled by a solenoid valve 457 is provided around the restriction and valve of regulator 449. Valve 457 is normally deenergized and closed. It is temporarily energized upon sudden throttle opening, as will be made clear, temporarily to by-pass flow of datum fuel as regards regulator 449 so as to relieve the pressure in the datum system, with resultant temporary increased opening of the nozzles N1 for mixture enrichment for acceleration. Whenever valve 457 opens to relieve pressure in the datum system, an auxiliary minimum datum pressure regulator 459 becomes efiective to prevent the datum pressure from dropping below a predetermined minimum, otherwise the system may become uncontrollable. Regulator 449 and valve 457 are assembled as a unit, though this is not essential.

The system of FIG. 12, like that of FIG. 1, includes thermostatic means immersed in the fuel in chamber C for varying the phase of the fuel metering rods 21 relative to the air measuring valve 7 of the air metering unit A in such manner as to provide for mixture enrichment when the engine is cold, bringing the metering rods to a normal phase position relative to valve '7 as the engine warms up. A fast idle control such as that shown for the FIG. 1 system may be used. The electrical components of the FIG. 12 system are connected in an electrical circuit generally indicated at BC]. in FIG. 23, this circuit including a throttle operated unloading switch U1 for clearing the engine of excess fuel when necessary.

The air metering unit of the FIG. 12 system The air metering unit A of the system shown in FIGS. 12 and 14 may be identical to that shown in FIG. 1, and the detailed description thereof need not be repeated. The conduit 1 of unit A appears in FIG. 12, also the air valve 7, servomotor 57 and economizer 79. The conduit 1, throttle valve 3 and air valve 7 appear in FIG. 15.

The fuel metering chamber of the FIG. 12 system The fuel metering chamber C of the FIG. 12 system may be substantially identical to that of the FIG. 1 system with the exception that there is no pipe such as indicated at 275 in FIGS. l3 in the chamber C (its place being taken by tube 407 in jacket 409). 7 Also, the thermostatic valve 295 and its housing 289 which appear in FIGS. 1-3 are omitted. Otherwise, the fuel metering relative rotation of levers 461 and 463.

1.5 chamber used in the FIG. 12 system is substantially the same as that used in the FIG. 1 system.

FIG. 22 shows one specific mode of thermostatically linking the magnetic coupling memberlZl in chamber C to the metering rod crosshead 23. As previously pointed out, magnetic coupling member 121 is rotatable on stud 1Z3 carried by plate 13.9. A lever 461 is fixed to the member 121 for rotation'therewith. A lever 463 is mounted on stud 123 for rotation relative to the member 121; Lever 461 has an arm 465 provided with a notch 4 57 which reecives a finger 469 on lever 4-63. Finger 469 is narrower than the notch 467 to permit limited Lever 4-61 has an ear 471 at its free end to which is secured one end of a bimetallic thermostatic blade 473. This blade extends from the car 471 back across the axis of the levers 46 and 463 and has its other end secured in a post 475 on lever 453. Link P9 is pin-connected at 477 to the free end of lever 463, The arrangement is such that as blade 473 (which is immersed in fuel in chamber C) heats up upon heating of fuel in chamber C, it bends and changes the angle or phase of lever 453 relative to lever 461 and member 121 (within the limits of movement of finger 469 in notch 457). This changes the phase of crosshead 23 and the metering rods 21 relative to member 12.1 and the air valve 7, with the arrangement such as to provide for increased fuel delivery through orifices 19 upon starting the engine under low engine temperature conditions and during warm-up of the engine, the rate of delivery being reduced as the engine warms up and ultimately reaching a normal value when the engine attains its operating temperature.

The equalizer valve of the FIG. 12 system Referring to FiG. 17, the equalizer valve 431 of the FIG. 12 system is shown to comprisea valve body 479 having an inlet 481 atone end to which the stem of T 4:29 is threaded. At the inner end of the inlet is a valve seat 433:. This seat is engageable by a valve 485 on a stem 487 extending through a passage 489 from which there is a lateral outlet port 491. The valve stem 487 is fixed in a solenoid plunger 493 slidable in a plunger case 45 5. Around this case is the solenoid coil 497. A spring 4%9 biases the plunger 493 and valve 485 in opening direction. The valve 455 is thus normally open, and is closed when the coil saw is eenrgized.

The nozzles of the FIG. 12 system As shown for the r 1G. 12 system, the nozzles N1 are clustered in groups of four, with one such group for each bank of four cylinders of the V8 engine. Each nozzle cluster NC comprises a bottom nozzle holder plate 591 and a top cap plate 593. The bottom plate Sill has four circular recesses such as indicated at 555, each of which constitutes a charging fuel chamber. The top plate 503 has four circular recesses such as indicated at 597 registering with the recesses 505, each recess 587 constituting a datum pressure chamber. As to each nozzle N1,

7 the respective charging fuel chamber 595 is separated from the datum pressure chamber 597 by a diaphragm 5%. Also as to each nozzle N1, a nozzle tube 511 is threaded in the bottom plate Sill coaxial with the diaphragm 5 39 and extends downward therefrom through a hole 533 in the engine intake manifold M1. A needle 53.5 has its upper end attached to the center of the diaphragm 5G9 and extends down through the nozzle tube 513., being slidable therein. A spring 517 biases the diaphragm 5 39 and needle 515 downward toward a position wherein the lower end of the needle engages the lower tip of the nozzle tube 511 to close the latter. The cross section of the needle 515 is such as to permit fuel to flow therearound through the nozzle tube and out of r the lower end or" the latter when the needle is raised.

Each top plate 503 has a boss 519 having four tapped holes 521 (see FIG. 14) to which are connected four of the fuel delivery lines 25 leading from fuel chamber C.

These holes 521 are in communication with suitable passages such as indicated at 523 (FIG. 16) formed in the bottom plate 501 to deliver fuel to the four charging fuel chambers. 595 of the cluster NC. The top plate 593 is formed with suitable datum passageways such as indicated at 525 interconnecting the four datum pressure chambers 597 of the cluster NC and there are front and rear bosses 527 and 529 (see H6. 12) on the top plate each having a tapped hole for connection thereto of fittings for connecting the cluster in the datum system. The top plate 593 is also formed with a central tapped inlet 531 in communication with the datum passageway system in the cluster NC. The nozzle clusters NC and manifold M1 may be of the same construction as shown in the copending Armstrong et al. application Serial No. 649,708, filed April 1, 1957, now Patent No. 2,915,049, for Ram Tube Manifold For Fuel Injection System, and reference may be made thereto for further details.

The datum pressure regulator of the FIG. 12 system As shown in detail in FIGS. 18 and 19, the datum pressure regulator R1 of the FIG. 12 system comprises two cups 533 and 535 having a diaphragm 537 clamped between their rims, and held together by screws 539. Cup 533 is provided with an inlet 541 to which isconnected the line 433 from T 4-29. Thus, chamber 543 defined by the cup 5.3-3 and the diaphragm 537 contains fuel at the same pressure as fuel chamber C. The diaphragm 537 carries a tubular valve seat member 545 at its center. An apertured retainer for the valve seat member is indicated at 547. This is on the side of the diaphragm 537 toward chamber 543. Member 545 is formed with a tapered seat 549 for a ball valve 551. Seat 549 flares in the direction toward chamber 543. A spring for biasing the ball 551 toward the seat is indicated at 553. A pin 555 is adjustably threaded in the center of the base of cup 535. The pin 555 projects into the tubular valve seat member 545 and its end is engageable by the ball 551. A sealing cap 557 encloses the outer end of the pin 555. Cup 535 and diaphragm 537 define a chamber 559. A spring 561 in chamber 559 biases the diaphragm 537 in the direction away from chamber 559 (toward the left as viewed in FIG. 18). A tube 563 extends tangentially of chamber 559. This tube has a restricted port 565 for entry of fuel from chamber 559 thereinto. Cup 535 has tapped ports 567 at the ends of tube 563 for connection of lines 441 and 443. Line 441 extends to and is connected to a fitting 569 (see FIGS. 12 and 14) connected into the hole in boss 527 at the forward end of one nozzle cluster NC. Line 443 extends to and is connected to a fitting 571 (seeFIGS. 12 and 14) into the hole in boss 527 at the. forward end of the other nozzle cluster.

With a predetermined differential in pressure /2 p.s.i., for example) between the fuel pressure in chamber 543 and the fuel pressure in chamber 559 (the value of this differential being dependent on the forceof spring 561), the diaphragm 537 is balanced. Pin 555 is adjusted so that when the diaphragm 559 is balanced, ball 551 is held slightly off its seat 549 to permit a low rate of fuel flow from chamber 543 to chamber. 559. If the pressure differential should increase, the diaphragm 537 moves toward the right (as viewed in FIG. 18). The ball 551 is held against movement toward the right by. the pin 555, and thevalve seat 549 moves away from the ball, thereby increasing the rate of fuel flow from chamber 543 to chamber 559 to bring the differential back down to the predetermined value. If the pressure differential should decrease, the diaphragm 537 moves toward the left. This permits the ball to close against its seat 549, and the differential is thereby brought back up to the predetermined value. 7

Referring to FIG. 20, the datum bleed-off regulator 17 and relief valve unit 449, 457 of the FIG. 12 system is shown to comprise a cup-shaped body 573 having a lateral tubular extension 575 and a bottom tubular extension 577. A diaphragm 579 is clamped against the rim of the cup-shaped body 573 by a cap'581 having a recess 583. A fitting 585 is threaded in the lateral extension 575. A flow-limiting spinner jet 587 is threaded in the inner end of the fitting 585. This jet has a cylindrical chamber 589. Fuel enters this chamber through a restricted radial port 591 and exits through a restricted axial port 593, a spinning action of the fuel being obtained in the chamber 589. Fuel exiting from the spinner jet 587 enters a space 595 in the wall of body 573. From this space there is a vertical passage 597 upward through a hole 599 in the clamped margin of the diaphragm 579 to a passage 601 in the cap 581 which leads to recess 583 in the cap above the diaphragm. A valve seat member 603 has one end threaded in a filler block 605 positioned in the cup-shaped body 573, and extends therefrom through an opening 607 in the wall of the body 573 to the space 595. Member 603 is formed to provide a tapered seat 609 adjacent its outer end for engagement by a valve ball 611. A spring 613 reacting from the spinner jet 587 biases the ball toward the seat 609. Thus, fuel exiting from the spinner jet 587 is supplied to the recess 583 above the diaphragm 579, and may flow through the member 603 to the chamber 615 defined by the diaphragm 579 and the cup-shaped body 573 when the ball 611 is off its seat 609.

Fitted in the bottom of chamber 615 is a ring 617. Pivotally mounted at 619 on this ring is a lever 621. Ring 617 supports a spider 623 formed to provide a tubular guide 625 for a vertically slidable rod 627. Rod 627 has a head 629 at its upper end engaging the bottom of the diaphragm 579. Springs 631 react from the spider 623 against the head 629 to bias the latter and the diaphragm 579 upward (in opposition to the pressure of fuel in recess 583). The lower end of the rod 627 engages the end of lever 621. Lever 621 is engageable with a pin 633 slidable in the valve seat member 603. Spider 623 is formed to allow for free flow of fuel from the space bounded by the ring 617 to the space above the spider, and fuel thence flows out through a lateral outlet 635 provided in the wall of body 573 opposite extension 575.

A plate 637 formed to provide a central downwardly directed annular valve seat 639 around a central hole 641 therein is threaded in the upper end of extension 577 (at the bottom of chamber 615). Extension 577 contains a solenoid coil 643, and is closed at the bottom by a plug 645. A solenoid plunger 647 carries a valve 649 at its upper end engageable with the seat 639. A spring 651 biases the plunger 647 upward so that valve 649 is norma'lly closed against the seat 639. When the coil 643 is energized, the plunger 647 is retracted to open the hole 641. Extension 577 has a lateral inlet port 653 above the coil 643. A coupler 655 is connected into the fitting 585 (see FIGS. 12 and 14). The datum holes in the rear bosses 529 of the two nozzle clusters NC are interconnected by a line 657, and a line 659 connects one of these datum holes to the coupler 655. Line 455 is connected between coupler 655 and inlet port 653. Line 451 extends from the outlet port 635 back to the tank 9.

When solenoid valve 457 is closed, regulator 449. is adapted to limit the return flow of datum fuel to the tank 9 and to maintain a predetermined minimum pressure in the datum system by the action of diaphragm 579 and ball 611. Spinner jet 587 acts as a restriction limiting the return flow, which occurs via the valve seat member 603 into the chamber 615 (ball 611 being normally slightly 011 its seat 609) and thence out through outlet port 635. If the datum pressure should drop (Within limits), the pressure in recess 583 drops, and springs 631 push the diaphragm 579 upward. This permits lever 621 to swing clockwise as viewed in FIG. 20,

18 and ball 611 is then moved toward its seat 609 by spring 613. This causes pressure in the datum system to build up to the predetermined minimum, at which point diaphragm 579 will have moved back down to act through the rod 627, the lever 621 and the pin 633 to unseat the ball 611.

Whenever solenoid coil 643 is energized, valve 649 is withdrawn from its seat 639, and fuel then flows directly from line 659 through line 455, hole 641, chamber 615, outlet port 635 and line 451 to the tank 9, by-passing the flow-limiting spinner jet 587. This drops the pressure in the datum system. If the pressure should tend to drop below the minimum of regulator 449, the auxiliary minimum datum pressure regulator 459 then comes into action, as will be made clear, to maintain the minimum datum pressure to avoid loss of control.

At this point, it may be mentioned that a vapor vent line 661 (see FIG. 12) may be provided extending from fuel chamber C to the regulator 449. For this purpose, the cap of 581 of regulator 449 has a tapped hole 663 for connection of the line 661. Also, spinner jets similar to the spinner jet "587 may be provided at each end of the vapor vent line 661.

The auxiliary minimum datum pressure regulator of the FIG. 12 system Referring to FIG. 21, the auxiliary minimum datum pressure regulator 459 of the FIG. 12 system is shown to comprise a cup-shaped base 663. A diaphragm 665 is clamped against the rim of the cup 663 by a cup-shaped head 667. A valve seat member 669 is threaded in the head. This is formed with an annular valve seat 671 around a central hole 673, the valve seat being on the side of member 669 away from the diaphragm 665. A line 675 (see FIG. 14) is connected between T 413 and a port 677 in the base. A line 679 connects a port 681 in the base to a port 683 in the head 667 above the valve seat member 669. A valve 685 is biased by a spring 687 to close against the valve seat 671. Diaphragm 665 carries a pin 689 which reaches through hole 673 for engagement with the valve 685. Diaphragm 665 is biased in the direction away from the valve seat member 669 by a spring 691. Between the diaphragm and the valve seat member, the head 667 has an outlet port 693. A line 695 (see FIG. 14) connects this port to the central datum inlet 531 of one of the nozzle clusters NC.

At normal datum pressures, diaphragm 665 occupies a position wherein pin 689 is withdrawn from the valve 685 to permit this valve to close against seat 671. When datum pressure drops below a predetermined minimum, however, pressure below the diaphragm 665 forces it upward, carrying pin 689 upward to unseat the valve 685. Fuel then flows from cup 663 through line 679 to the head 667, thence through hole 673 in member 669, and out through outlet port 693 and line 695 to the datum system.

The electrical circuit and unloader of the FIG. 12 system Referring to FIG. 23, at 701 is indicated the battery of .he vehicle. One terminal of the battery is grounded as indicated at 703. A line 705 extends from the other terminal of the battery to one terminal of the ignition switch 707 of the vehicle. A line 709 extends from the other terminal of the ignition switch to one terminal of the starter switch 711 of the vehicle. A line 7'13 extends from the other terminal of the starter switch to one terminal of the coil 715 of a normally open starting enrichment relay 717. The other terminal of the coil is grounded as indicated at 719. The normally open contacts of relay 717 are indicated at 721. A line 723 extends from the stated other terminal of the starter switch 711 to one terminal of the coil 725 of a normally closed unloader relay 727. A line 729 extends from the other terminal of the coil 725 to one terminal of unloader switch U1. The other terminal of this switch is grounded as indicated at 731. Switch U1 is normally open, being closed by a.

linkage such asindicated at 733 when the accelerator pedal 49 of the vehicle is pushed to open the throttle valve 3 wide. The normally closed contacts of unloader relay are indicated at 735. These are connected in a line 737- in series with the ignition switch 707 extending to one terminal of the equalizer valve solenoid coil 497. The other terminal of coil 497 .is grounded as indicated at 739. Normally open contacts 721 of the starting mixture enrichment relay 717 are connected in a line 741 extending from line 737 to one terminal of datum relief valve solenoid coil 643, in series with unloader relay contacts 735. The other terminal of coil 643 is grounded as indicated at 743.

At 745 is indicated a normally open acceleration switch. This is series-connected with a resistor 747 in a line 749 in parallel with relay contacts 721. Means is provided for temporarily closing switch in response to sudden opening of the throttle valve 3 (i.e., sudden pressing down of accelerator pedal 49). As shown in FIG. 23, this means comprises a cylinder 751 having a flexible diaphragm 753 at one end. Slidable in the cylinder is a piston 755. A piston rod 757 extends from the piston through the other end of the cylinder and is interconnected to the accelerator pedal linkage as indicated at 759. Cylinder 751 has a bleed hole 761 toward its diaphragm end. The diaphragm 753 is engageable with an actuating arm 7630f switch 745. Theswitch 745 is biased to open. When the pedal 49 is depressed for rapid acceleration, the piston 755 is rapidly moved toward the diaphragmend of the cylinder 751 to compress the air in the cylinder ahead of the piston (the bleed hole 761 being small enough to hold the compression for a time). This bulges out the diaphragm 753 to close the switch 745. The switch 745 remains closed until sufiicient air has bled out through the bleed hole 761 to allow the opening bias of the switch 745 to overcome the air pressure on the diaphragm 753, and then the switch opens.

Operation of the FIG. 12 system Under normal operating conditions, the ignition switch 707 is closed, and the starting switch 711 is open. With theignition switch closed and with unloader switch U1 open so that the unloader relay coil 725 is deenergized and the unloader relay contacts 735 are closed, a circuit for the equalizer valve coil 497 is completed via line 705, switch 707 (closed), line 709, and line 737. With coil 497 thus energized, the equalizer valve 431 is closed. With the starter switch 711 and the acceleration switch 745 open, coil 643 of datum pressure relief valve 457 is deenergized, and the relief valve 457 is closed. The engine B being in operation, pump 401 is in operation to deliver fuel from the tank 9 to fuel chamber C, and the latter is maintained full of fuel under pressure. Fuel is supplied from chamber C to the datum pressure system via lines 427 and 433 (the equalizer valve 4'31being closed), and fills the chambers 543 and 559 of the datum pressure regulator R1, lines 441 and 443, the datum pressure chambers 507 of nozzles N1, and lines 657 and 659. Withrelief valve 457 closed, fuel flows continuously at a low rate from chamber C through the datum pressure system and back to the tank 9, the low rate resulting from the flow-limiting effect of the spinner jet 587 at the end of line 659. Valve 611 is adapted to maintain a predetermined minimum pressure in the datum pressure system, as previously explained.

Regulator R1 is adapted to maintain a predetermined pressure diiferential between the charging pressure (i.e., the pressure in chamber C) and the datum pressure (i.e., the pressure in chambers 507 of nozzles N1), with the datum pressure lower than the charging pressure during all normal rates of flow. This pressure differential may be about p.s.i., for example, and it is maintained except upon sudden acceleration as will be made clear. The regulator R1 acts in accordance with variations in the pressure'in chamber C to maintain the stated pressure differential as follows: Upon a decrease in charging pressure in chamber C, the presure in regulator chamber 543 drops. Diaphragm 537 thereupon moves toward the left as viewed in FIG. 18. This brings the ball 551 closer toits seat 549. Accordingly, the-rate of fuel supply to chamber 559 is reduced relative to the rate of escape of fuel from chamber 559, and the datum pressure (the pressure in chamber 559) is dropped an amount equal to the drop in charging presure, so that the difference between charging pressure and datum pressure remains the same. Upon an increase in charging pressure in chamber C, the pressure in regulator chamber 543 increases. Diaphragm 537 thereupon moves toward the right as viewed in FIG. 18. This brings the ball 551 farther away from its seat 549. Accordingly, the rate of fuel supply to chamber 559 is increased relative to the rate of escape of fuel from chamber 559, and the datum pressure is increased an amount equal to the increase in charging pressure, so that the difference between charging pressure and datum pressure remains the same.

As to each nozzle N1, the nozzle diaphragm 509 is subject on one side to charging pressure in chamber 505 tending to move the nozzle needle 515 upward away from its seat, and subject on the other side to datum pressure in chamber 507 and the force of the nozzle spring 517 tending to move the nozzle needle downward toward its seat. With the charging pressure high enough to overcome the closing force on the nozzle needle 515 due to the datum pressure and spring 517, the needle is unseated, and fuel is discharged through the top of the nozzle. As in the FIG. 1 system, the rate of flow of fuel through a nozzle is dependent upon the position of the metering rod 21 related to that particular nozzle in relation to the metering rod orifice 19 and the pressure drop across the orifice. As long as the pressure differential between charging pressure and datum pressure remains substantially constant, the pressure crop across orifice 19 remains substantially constant, being equal to the stated pressure differential plus the pressure created by the nozzle spring 157 (which is a low rate spring). Thus, the pressure drop across orifice '19 is normally maintained substantially constant, and variations in the rate of flow of charging fuel are caused solely by moving the metering rods 21 in or out, the farther in the rods, the lower the rate of flow, and vice versa.

As in the FIG. 1 system, the position of the metering rods 21 is dependentupon the position of air valve 7 and the temperature of thermostatic member 473 which is immersed in the fuel in chamber C. The position of the air valve is dependent upon the rate of air flow through the conduit 1. The temperature of thermostatic member 473 is dependent upon the temperature of engine E. Assuming that the engine is fully warmed up, the eifect of temperature on the position of the rods may be disregarded, and with the air valve 7 closed, the metering rods 21 will occupy an advanced position wherein the efiective area of each orifice 19 (the annular area around the rod within the orifice) is a minimum, for flow of charging fuel at a minimum rate corresponding to the rate of flow of air to the engine. As the air valve 7 opens with increase in the rate of air flow, the metering rods 21 are withdrawn an amount proportional to the opening of the air valve to increase the rate of flow of charging fuel proportionately to the increase in the rate of air flow. Also as in the FIG. 1 system, in the part throttle range the opening of the air valve 7 is atenuated by the economizer 79 to attenuate the withdrawal of the metering rods to provide a lower rate of flow of charging fuel than would occur without such attenuation, so as to deliver an economy mixture of air and fuel to the engine. In the full throttle range of operation, wherein the air valve 7 has opened to the point where port 97 is downstream from the air valve, the attenuating eifect of the economizer 79 is decreased, and the metering rods 21 are withdrawn to the point of providing the necessary rate 

